http_proxy2

package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
)

var Established = []byte("HTTP/1.1 200 Connection Established\r\n\r\n")

type ProxyServer struct {
	Travel *http.Transport
}

func (p *ProxyServer) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodConnect {
		p.HttpsHandle(rw, r)
	} else {
		p.HttpHandle(rw, r)
	}
}

func (p *ProxyServer) HttpHandle(rw http.ResponseWriter, r *http.Request) {
	fmt.Println(r.URL)
	resp, _ := p.Travel.RoundTrip(r)
	fmt.Println(rw.Header())
	for k := range rw.Header() {
		rw.Header().Del(k)
	}
	for k, values := range resp.Header {
		for _, v := range values {
			rw.Header().Add(k, v)
		}
	}
	rw.WriteHeader(200)
	io.Copy(rw, resp.Body)
}

func (p *ProxyServer) HttpsHandle(rw http.ResponseWriter, r *http.Request) {
	hj, _ := rw.(http.Hijacker)
	client, _, _ := hj.Hijack()
	conn, _ := net.Dial("tcp", r.URL.Host)

	client.Write(Established)

	go io.Copy(client, conn)
	go io.Copy(conn, client)
}

func NewProxyServer(addr string) *http.Server {
	log.Println("listen", addr)
	return &http.Server{
		Addr:    addr,
		Handler: &ProxyServer{Travel: &http.Transport{}},
	}
}

func main() {
	server := NewProxyServer(":8080")
	server.ListenAndServe()
}